Problem using dual monitors with Radeon 9000 Pro and 2 x Samsung SM223BW

Question

Hello all
I really need an expert opinion here:
I am using quite a lot my MDD 1.25Ghz that is still equipped with the OEM ATI 9000 Pro Mac Edition with 64MBs of Video RAM and as most if not all Mac-specific cards it has an ADC and a DVI port. I recently purchased a couple of Samsung monitors; the afore mention in the subject SM223BW. The monitors have two inputs, both DVI and D-SUB (Analog VGA or otherwise plain old RGB).
I have purchased a Formac ADC to DVI converter and connected this output to the DVI input of the first monitor. It works like a charm and the picture quality it is quite good (not as with an Apple Display but I couldn't afford them at this stage). For the second monitor I used a DVI to VGA cable (going from the DVI output of the card to the VGA In of the monitor).
Now here is the problem: The monitor that is connected ADC to DVI has all the available 16:10 ratio option that are suitable for this monitor. The DVI to VGA one gives me only a 1680x1050 and all the rest are 4x3 resolutions.
Would anyone know why this happens? Could it be a monitor issue? Could it be that perhaps TFT monitors offer different resolutions according to the input used. Or could it be the graphics card? Or even perhaps the cable?
Under OS X, same settings and same computer I am given more resolution options. Would that mean that it might be as well my beloved OS 9 in combination with the card?
Or am I stressing this too far?
Please any ideas are more than welcome
PS: I have a dual 2.0Ghz G5 connected to the rest of the DVI and VGA inputs to be able to run both without having to repatch. Otherwise a DVI to DVI connection would have made more sense and solved the problem

Answer 1

Hey Simon
I bought these monitors for their dual input functionality. The reason that I have the G4 connected to VGA is because I have another G5 connected the other way around in order to be able to use both computers, at any given time, with two screens.
Perhaps to make clear the connections I've done (if of course anyone is interested :)) ...
The G4 connects via ADC to DVI to the DVI input of Monitor No.1
The G5 connects via VGA to VGA to Monitor No.1
The G4 connects via DVI to VGA to Monitor No.2
The G5 connects via DVI to DVI to Monitor No.2
Another question would be why simply one mac isn't connected solely via DVI and the other one via VGA? The reason is that the VGA input looks awful on these screens for whatever reason. The image is seriously not sharp, the fonts looks horrendous and even with a lot of tweaking from the monitor settings, still I'd say the image is minging. If anyone knows why a VGA input can look that bad and still a monitor being in the market please let me know. It could be that this monitor is aimed to PC users and with the accompanying PC-only drivers all such are non-existent...Anyway I decided to go with the half DVI-half VGA solution to get the best out of the situation.
But on the question asked, I decided to use a 2 DVI input Avocent KVM that I've got with interesting results. I am pretty sure it is boring to read but if anyone has spare time here it goes:
The G4 connects via ADC to DVI to Monitor 1.
Monitor 2 DVI output connects to DVI KVM Input
The G4 connects via DVI to DVI to KVM Output 1
The G5 connects via DVI to DVI to KVM Output 2
The G5 still connects via VGA to VGA to Monitor 2
In this manner I am guaranteed to utilize the DVI inputs for both monitors, at least on my G4 and the G5 be forced to utilize one VGA. The plus side of the situation is that I can use both systems with the flick of a button without having to get up to change the Source on the monitors plus of course one keyboard and a mouse. Now here is the interesting bit:
Under OS 9, with the resolution 1280x800 on Monitor No.1 (the one connected via ADC to DVI) flips to - I think - 1680x1050 - it could be higher than that - with a thick black frame around the Desktop occupying a good chunk of the screen and the actual OS 9 looking minuscule at the center of it.
Monitor No.2 (the DVI to DVI connected one) looks just fine.
Now on top of that, when the G5 is switched on but the KVM is outputting the G4 desktop on Monitor No.2, whenever the mouse cursor slides on this monitor, it goes black! Just simply black and when I move the mouse cursor back on Monitor No.1 goes Desktop again.
Under OS X, none of the afore mentioned problems exist. Everything runs fine and I am give more 16:10 resolutions as well.
Confused? I am